NEW DELHI: The Air Force and the Navy have kept their aircraft on standby and are waiting for final instructions for taking part in the search operations for locating the missing Malaysian plane with 239 people on board, Defence Ministry said today.

"Indian aircraft, reconnaissance assets are ready and on standby. We are waiting for specific request from Malaysia before commencing operation," Defence Ministry officials said.

The search area for the IAF is likely to be the Malacca Straits near the Andaman and Nicobar Islands.

The IAF has its Dornier aircraft along with the Mi-17 helicopters deployed in the Island territory and if the need be, the Navy can deploy the P-8I and the Tu-142 maritime surveillance aircraft.

The Coast Guard Dornier aircraft are also expected to be pressed into action.

Malaysia has sought India's assistance to trace its missing aircraft as the government here initiated the process of appointing designated people to share information and take the matter forward.

The Beijing-bound Malaysia Airlines Boeing-777 plane, which had five Indians on board, vanished over the South China Sea on Friday an hour after taking off from Kuala Lumpur.

India has a tri-services military command at Andaman and Nicobar islands and Navy and air force carry out regular patrols in the area.

Search and rescue operations which had been mobilised since early Saturday morning have failed to find the jetliner in the South China Sea and authorities have expanded the area of search into the Andaman sea, Malaysian officials said.

Authorities have put the plane's last known point of contact with air-traffic control off eastern Malaysia - roughly midway between Kota Bharu and the southern tip of Vietnam, flying at 35,000 feet.